Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTION
The present invention relates to catheters.
A various assortment of catheters, such as urinary
catheters and endotracheal tubes, have been proposed for use in
patients. In the case of urinary catheters, Foley catheters are
commonly constructed with a shaft having a drainage lumen and an
inflatable balloon adjacent a distal end of the shaft. During
placement, a distal end of the catheter is passed through the
patient's urethra until the balloon and drainage eyes, which
communicate with the drainage lumen, are located in the patient's
bladder, and the balloon is inflated through an inflation lumen
to retain the catheter in place. During catheterization, urine
drains through the drainage eyes and lumen and through a drain-
age tube connected to a proximal end of the catheter to a drain-
age bag for collection therein.
Conventional catheters of this sort were made fromlatex rubber through dipping techniques known to the art. In
time, it was discovered that the latex catheters were not com-
pletely satisfactory since layers of the dipped material occa-
sionally became delaminated during use, thus causing blockage inthe inflation lumen and obstructing deflation of the balloon
when it was necessary to remove the catheter from the patient.
As a result, it became desirable to construct the catheter shaft
from a material which may be extruded in order to prevent pos-
sible blockage of the inflation lumen, and reduce the cost ofthe catheter to the patient due to simplfied manufacturing tech-
niques.
In turn, the materials which appeared satisfactory
for use as a shaft posed new problems in construction of the
catheter. For example, it became necessary to find suitable
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materials for the ba]loon which are sufficiently elastic to per-
mit inflation during use, and which are compatible with the
selected shaft for bonding purposes. Frequently, materials
which appeared otherwise satisfactory for the catheter shaft and
balloon proved to be incompatible when attempts were made to
bond the balloon ~o the shaft through use of adhesive or sealing.
In addition, it became necessary to secure a tip to the distal
end of the extruded shaft, and a connecter to the proximal end
of the shaft. Such tips and connecters have been formed sepa-
rately, and have been adhered to the shaft. However, in thecase of the connecters, it is necessary to establish communica~
tion between lumens in the connecter and the associated infla-
tion and drainage lumens in the shaft. In the case of the tips,
it is necessary to obtain a sufficient bond of the tip to the
distal end of the shaft while closing the distal end of the
inflation lumen. In both cases, difficulties have been encoun-
tered in obtaining the proper alignment of lumens and achieving
the desired bond. In addition, it has been necessary in the
past to separately form an opening in the outer surface of the
shaft to obtain communication between the inflation lumen and a
cavity beneath the balloon. All of the excessive operations and
difficulties associated with construction of the catheter dele-
teriously affect the capability of providing the catheter, which
is considered a disposable item, at a significantly reduced cost.
SUMMARY OF THE INVENTION
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A principal feature of the present invention is the
provision of a catheter of simplified construction and reduced
cost.
The catheter of the present invention comprises, an
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elongated shaft having a main lumen extending through the shaft,
and an inflation lumen extending through a wall of the shaft.
The catheter has a tip molded directly onto a distal end of the
shaft, with the tip having a lumen communicating with the main
lumen of the shaft, and at least one opening adjacent a distal
end of the tip communicating with the tip lumen. The molded tip
defines a distal end portion of the inflation lumen and an aper-
ture at an outer surface of the tip. The distal end of the shaft
and the proximal end of the tip have complementary beveled por-
tions defining juncture surfaces which are bonded together. The
catheter has a connecter directly bonded onto a proximal end of
the shaft, wiih the connecter having a lumen communicating with
the shaft drainage lumen, and an inflation lumen in a side arm
communicating with the inflation lumen of the shaft. The connec-
ter and proximal end of the shaft have complementary beveled por-
tions defining juncture surfaces, and the shaft has a proximal
end portion defined by the bevel which is outwardly flared in
the molded connecter. The catheter also has a sleeve of elastic
material secured to the catheter in spaced circumferential zones
and defining a cavity communicating with the inflation lumen.
A feature of the present invention is that the beveled
portions at the proximal and distal ends of the catheter shaft
define an enlarged surface area to achieve an enhanced bond
between the shaft and the catheter tip and connecter.
Another feature of the invention is that the distal
end portion of the inflation lumen is automatically formed in
the tip during molding of the tip.
A further feature of the invention is that an aperture
is defined at the distal end of the inflation lumen in the tip
during molding of the tip.
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Yet another feature of the invention is that the out-
wardly flared proximal end portion of the catheter shaft ensures
structural continuity and integrity between the inflation lumens
of the shaft and connecter.
A feature of the present invention is that the cathe-
ter shaft is insert molded onto the tip and connecter in a simpli-
fied manner without the use of adhesive.
A furlher feature of the invention is that the catheter
may be made at a reduced cost.
Another feature of the invention is the provision of
methods for constructing the catheter of the present invention.
Further features will become more fully apparent in the
following description of the embodiments of this invention and
from the appended claims.
DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a fragmentary elevational view of a catheter
of the present invention;
Fig. 2 is a fragmentary sectional view of the catheter
of Fig. l;
Fig. 3 is a fragmentary plan view of a mold for forming
a tip on a distal end of a catheter shaft;
FigO 4 is a perspective view of a main pin for use in
the mold of Fig. 3;
Fig. 5 is a fragmentary plan view of a mold for forming
a connecter onto a proximal end of the catheter shaft; and
Fig. 6 is a fragmentary schematic view of separate
molds being used to simultaneously form a tip and connecter onto
a catheter shaft.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
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Referring now to Figs~ 1 and 2, there is shown a cathe-
ter generally designated 10 having an elongated extruded shaft 12,
a tip 14 secured to a distal end 16 of the shaft 12, and a connec-
ter 18 secured to a proximal end 20 of the shaft 12. The shaft
12 has a main or drainage lumen 22 extending through the shaft,
and an inflation lumen 24 extending through a wall of the shaft.
The tip 14 has a main lumen 26 communicating with the
main lumen 22 of the shaft 12, and a pair of drainage eyes or
openings 28 extending to an outer surface 30 of the tip 14, and
communicating with the main lumen 2Ç of the tip. The tip has a
closed distal end 32, and the tip defines a distal end portion 34
of the inflation lumen 24 and an aperture 36 at the outer surface
30 of the tip communicating with the lumen portion 34.
The connecter 18 has a connecting portion 38 defining
a proximal end 40 of the catheter 10 and defining a main lumen 42
of the connecter 18 communicating with the drainage lumen 22 of
the shaft 12. As shown, the proximal end of the connecter lumen
42 is enlarged to receive an adapter of a drainage tube (not
shown), and the connecter 18 has a plurality of annular sealing
rings 44 in the lumen 42 to snugly engage against the drainage
tube adapter. The connecter 18 has a side arm 46 defining an
inflation lumen 48 which communicates with the inflation lumen 24
of the shaft 12, and a recess 50 at a proximal end 52 of the side
arm 46 to receive suitable valve means 54 for controlling passage
of fluid through the inflation lumen of the shaft and connecter.
As shown, the connecter 18 has a distal annular flange 56 engag-
ing against an outer surface 58 of the shaft 12 and enclosing
the proximal end 20 of the shaft.
The catheter also has an annular sleeve 60 of elastic
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material forming a balloon adjacent a distal end of the catheter.
The sleeve 60 has a pair of opposed ends 62a and 62b which are
respectively secured in circumferential zones 64a and 64b to the
outer surface 30 of the tip 14 and the outer surface 58 of the
shaft 12. In this configuration, the sleeve 60 defines a cavity
66 underlying a central portion 68 of the sleeve 60 which commu-
nicates with the inflation lumen through the tip aperture 36.
As shown in Fig. 2, the shaft 12 has a beveled distal
end which defines a tapered juncture surface 70 disposed at an
acute angle relative to the lower surface of the shaft as shown
in the drawing. In turn, the tip 14 has a beveled proximal end
72 which defines a complementary juncture surface 74 disposed at
an obtuse angle relative to the lower surface of the shaft as
presented in the drawing, with the surfaces 70 and 74 facing
each other and being secured together to bond the tip 14 to the
shaft 12. As shown, the tip aperture 36 is located intermediate
ends of the beveled portions of the tip and shaft.
The shaft 12 also has a beveled proximal end defining
a juncture surface 76 disposed at an acute angle relative to an
upper surface of the shaft as presented in the drawings, such
that the proximal beveled shaft portion defines a tapered end
portion 78 containing the proximal end 80 of the shaft inflation
lumen 24, with the inflation lumen end 80 being disposed at the
apex of the acute angle. The connecter has a complementary bev-
eled juncture surface 82 which is disposed at an obtuse anglerelative to the upper surface of the shaft as presented in the
drawing. In a preferred form, the acute angles at both the
proximal and distal ends of the shaft may range from 30 to 45
degrees. The juncture surfaces 76 and 82 of the shaft 12 and
connecter 18 face each other and are secured together inside the
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connecter 18. As shown, the shaft 12 may be longitudinally sev-
ered along a line 84 at the proximal end 20 of the shaft 12,
with the line 84 being located intermediate the inflation lumen
24 and the opposed surface of the catheter shaft, such that the
severance line 84 defines a flap 86 at the tapered end portion
78 containiny the proximal end 80 of the shaft inflation lumen
24. As shown, the flap 86 is outwardly flared in the connecter
18, such that the flap 86 defines a curve in the proximal end 8
of the shaft drainage lumen 24, and spaces the proximal end 80
of the inflation lumen 24 from the main lumens 22 and 42 of the
shaft 12 and connecter 18, respectively. In this manner, the
outwardly flared flap 86 assures continuity and integrity between
the inflation lumen 24 of the shaft 12 and the inflation lumen 48
of the connecter 18 without leakage into the main lumens of the
catheter shaft or connecter. However, it is noted that the
tapered end portion 78 of the shaft 12 may be placed in the out-
wardly flared confiyuration without the severance line 84 due to
the tapered configuration of the shaft proximal end 20.
As will be seen below, the tip 14 and connecter 18 are
molded directly onto the distal and proximal ends of the shaft,
such that the tip and connecter are bonded to the shaft without
the use of adhesive. In a preferred form, the shaft 12 and
sleeve 60 may be extruded from a suitable elastic material. The
tip 14 and connecter 18 may then be molded onto the catheter
shaft 12, and the sleeve 60 may be bonded onto the tip and shaft
after removal of the catheter from the molds. In a preferred
form, the shaft 12 and sleeve 60 may be extruded from the same
material of which the tip 12 and connecter 18 are molded, and,
in a suitable form, the shaft 12, tip 14, connecter 18, and
sleeve 60 may be constructed from a thermoplastic elastomer such
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as Kraton, a trademark of Shell Oil Company.
Referring now to Fig. 3, there is shown a mold 88 hav-
ing a cavity 90 for insert molding the distal end 16 of the
catheter shaft 12 onto a tip as will be described below. First,
the distal end 16 of the catheter shaft 12 is severed at an angle
to define the tapered end portion of the catheter shaft. Next,
a proximal end 92 of a main pin 94 is inserted into the distal
end of the shaft main lumen 22 in order to close the distal end
of the main lumen 22. With reference to Figs. 3 and 4, the main
pin ga~ has an elongated core 96, and a pair of opposed ears 98a
and 98b extending outwardly from the core 96 adjacent a distal
end 100 of the main pin 94.
As shown in Fig. 3, a proximal end 102 of an auxiliary
pin 104 is inserted into the distal end of the shaft inflation
lumen 24 in order to close the distal end of the inflation lumen.
As shown, the auxiliary pin 104 has a central portion 105 extend-
ing distally from the shaft and aligned with the inflation lumen
24. The pin 104 also has an outwardly turned distal end portion
106 which is spaced from the distal end of the shaft 12, and
which is located intermediate the ends of the beveled distal
shaft portion.
The distal end 16 of the catheter shaft 12 is placed in
a channel 108 of the mold 88 while the main pin 94 and auxiliary
pin 104 are placed in the mold cavity 90. In this configuration,
the catheter shaft 12 closes the proximal end of the mold cavity
90, while the end portion 106 of the auxiliary pin 104 extends
to the wall of the cavity. In addition, the ears 98a and b of
the main pin 94 extend to walls of the cavity 90 and support the
core 96 and dista~ end 100 of the main pin 94 at a location
spaced from walls of the cavity 90. The end portion 106 of the
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auxiliary pin 104 and the elongated ear 98b of the main pin 94
are received in a block positioned in recess 110.
After placement of the pins and shaft in the mold 88,
a molten material, such as a heated thermoplastic elastomer mate-
rial, is injected through a gate 112 into the mold cavity 90 toform the catheter tip. The gate 112 is located adjacent the dis-
tal end of the shaft in order that the hottest material contacts
the shaft and obtains an excellent bond between the shaft and tip.
In addition, the gate 112 directs the material against the core
96 in order to spread the material and maintain the desired tem-
perature of the material in the cavity. After the tip has suffi-
ciently cured, the block in recess 110 is utilized to remove the
pins and tip from the cavity 90. With reference to Figs. 2 and
3, the core 96 of the main pin 94 defines the lumen 26 of the
tip 14, while the ears 98a and b form the opposed drainage eyes
28 in the tip. The molded tip may be flexed slightly in order to
pass the distal end of the tip over the shorter ear 98a. Next, a
source of pressurized gas may be connected to the proximal end of
the catheter main lumen in order to blow the catheter off the
main pin 94 while retained in the block. Hence, the main pin 94
passes through one of the drainage eyes formed in the tip, and
at the same time, the auxiliary pin 104, which is also retained
by the block, is removed from the catheter through the opening
36. The central portion 105 of the auxiliary pin 104 forms the
distal end portion 34 of the inflation lumen in the tip 14, while
the distal end portion 106 of the auxiliary pin 104 forms the
end of the inflation lumen and the tip aperture 36. Thus, the
catheter tip 14 is molded directly onto the distal end of the
catheter shaft 12 in a simplified manner while forming the lumen
and drainage eyes in the catheter tip. In addition, the auxili-
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ary pin 104 conveniently forms the distal end of the inflationlumen and automatically forms the aperture 36 communicating with
the inflation lumen at the outer surface of the tip. The tapered
juncture surfaces of the catheter shaft and tip define an
enlarged surface area to enhance the bonding strength between
the catheter shaft and tip and minimize the possibility of sever-
ance during use. As previously indicated, the catheter sleeve
60 may be bonded to the catheter shaft and tip after formation
of the tip.
With reference to Fig. 5, a mold 114 is utilized to
form the catheter connecter in a cavity 116 as described below.
First, the proximal end 20 of the catheter shaft 12 is severed
at an angle to form the beveled end portion of the catheter
shaft, and the shaft 12 may be also severed along the line 84 to
define the flap 86 at the proximal end of the shaft, if desired.
Next, the distal end 118 of a main pin 120 is inserted into the
proximal end of the shaft main lumen 22 in order to close the
proximal end of the shaft lumen 22. In addition, the distal end
122 of an elongatecl auxiliary pin 124 is inserted into the proxi-
mal end of the shaft inflation lumen 24 to close the proximal end
of the inflation lumen 24. The proximal end 20 of the catheter
shaft 12 is placed in a channel 126 of the mold 114 in order to
close the distal end of the cavity 116 while the main pin 120
and auxiliary pin 124 are positioned in the mold cavity 116. In
this configuration, a proximal end 128 of the main pin 120
closes the cavity and supports an elongated core 130 of the main
pin 120 at a position spaced from walls of the cavity 116. As
shown, the main pin core 130 has a plurality of spaced circumfer-
ential recesses 132 for a purpose which will be described below.
A proximal end 134 of the auxiliary pin 124 closes a proximal
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end of the cavity 116, and supports an elongated central cylin-
drical section 136 and an enlarged proximal portion 138 at a
location spaced from the walls of the cavity 116. In this con-
figuration, a curved portion 140 of the auxiliary pin 124 in the
flap 86 retains the flap 86 in an outwardly flared configuration
preparatory to forming the connecter.
A suitable molten material, such as a thermoplastic
elastomer material, is injected through a flared fan gate 142
into the mold cavity 116 in order to form the connecter. The
gate 142 is relatively thin in width and has a considerable
length, such that the gate 142 spreads the molten material as it
passes into the cavity 116. The gate 142 is located adjacent
the proximal end of the catheter shaft in order that the hottest
material contacts the shaft to achieve an excellent bond between
the shaft and connecter. In addition, the gate 142 directs the
molten material onto the core 130 of the main pin 120 in order
to enhance spreading of the material in the cavity and maintain
temperature of the material in the mold. The configuration of
the gate 142 also minimizes the scar on the connecter along a
thin line after molding has been completed, although the gate
142 is capable of rapidly injecting a large amount of material
into the cavity.
After the connecter has sufficiently cured, the cathe-
ter and pins are removed from the cavity. With reference to
Figs. 2 and 5, the core 130 of Ihe main pin 120 forms the main
lumen 42 of the connecter 18 while the recesses 132 form the con-
necter sealing rings 44. The main pin 120 may be removed through
an opening formed at the proximal end of the connecter 18 while
the auxiliary pin 124 may also be removed by flexing the side arm
46 of the connecter 18 slightly and drawing the auxiliary pin
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through an opening at the proximal end of the side arm. The cen-
tral section 136 of the auxiliary pin 124 forms the inflation
lumen 48 in the connecter side arm, while the enlarged proximal
portion 138 of the auxiliary pin 124 forms the recess 50 for ihe
valve means. As constructed, the connecter flange 56 surrounds
and encloses the proximal end 20 of the catheter shaft 12. In
addition, the connecter 18 has material extending around the
proximal shaft flap 86 surrounding the proximal end of the infla-
tion lumen while the outwardly flared flap 86 in the connecter
18 assures continuity and integrity between the inflation lumen
24 of the shaft 12 and the inflation lumen 48 of the connecter
side arm 46. The tapered juncture surfaces of the shaft and con-
necter provide additional surface area to enhance the bond
strength between the catheter shaft 12 and connecter 18.
Thus, in this manner the catheter tip and connecter
may be formed and bonded to the catheter shaft in a molding oper-
ation which assures simplicity in the manufacturing process of
the catheter while achieving an excellent bond between the tip
and connecter and the catheter shaft. With reference to Fig. 6,
it will be seen that the proximal and distal ends 20 and 16 of
the catheter shaft 12 may be inserted into the tip mold 88 and
connecter mold 114 in order to simultaneously insert mold the
catheter shaft onto the catheter tip and connecter. Of course,
the cavities for the tip and connecter may be placed in a single
mold for simultaneous molding of the tip and connecter to the
catheter shaft in one mold, if desired.
The foregoing detailed description is given for clear-
ness of understanding only, and no unnecessary limitations should
be understood therefrom, as modifications will be obvious to
those skilled in the art.
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